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(No Model.) 8 Sheets-Sheet 1.

O. OEXLE. Roller Mill for Grinding Grain, 81:0.- No. 240,453. PatentedApril 19,188l.

3 Sheets-Sheet 2.

(No Model.)

, 0. OEXLE. Roller Mill for Grinding Grain, &c. No. 240,453. PatentedApril 19,1881.

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0.. OEXLE. I v Roller M111 for Grinding Grain, 8m. No. 240,453. PatentedApril 19,1881".

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z I Q r \w\\\ {CM MPETERS, PHOTO-LITHOGRAPMER, WASHINGTON, D c.

UNrran STATES.

PATENT Grin ca.

OSCAR OEXLE, OF AUGSBURG, BAVARIA, GERMANY.

' ROLLER-MILL FOR GRINDING GRAIN, 800.

SPECIFICATION formingpart Of Letters Patent NO. 240,453, dated April 19,1881. Application filed J nly 29,1880. (No model.) Patented in GermanyApril 2, 1880.

To all whom "it may concern Be it known that I, OSCAR OEXLE, civilengineer, of Augsburg, in the Kingdom of Bavaria, Germany, have inventedcertain new and useful Improvements in Roll-Mills for Grain and otherSubstances, of which the following is a specification.

My invention relates to improvements in roll-mills for disintegratingwheat-kernels preparatory to the manufacture of flour; and the objectsof my improvements are to break or cut the kernels of wheat in theirlongitudinal axis to open the crease or groove in their first reduction,for the purpose of freeing or detaching as complete as possible the darkdust and the germ from the crease and produce large coarse-sizedniiddlings, whereby to facilitate the separation of the crease-dust andthe germ from the broken particles, to efi'ect such crease cleaning withthe least possible production of flour, to reduce middlings, and toclean the bran. I attain these objects by the mechanism illustrated inthe accompanying drawings, in which- Figure 1 represents a roll'mill,partly in vertical section and partly in side elevation, embracing myinvention; Fig. 2, a view partly in horizontal section and in top view;Fig. 3,

. the rolls, in cross-section, on an enlarged scale,

independently of the adjustment of the roll, means for limiting theminimum distance between the rolls, and means for determining thedistance the adjustable roll may yield from the other independently ofthe means by which said roll is adjusted and pressed forward; and Fig.6, a horizontal section of the same, these views being on enlargedscales.

The rolls are formed with sharp ridges or scores, extending from end toend parallel to their axis, of ratchet, or approximately ratchet, form,and in which the interdent-al spaces present in one roll the apices ofthe ridges moving upward and those of the other roll moving downwardatthe point of operation or reduction, so that the shortest or radialsides of the ridges of the rolls must travel facing upward in one rolland downward in the other roll at the point of operation upon the grain,or at which the grain is delivered upon them, while the rolls themselvestravel in the same direction. The roll in which the apices of the-ridges travel downward, as stated, is geared to run at a high speed,while the roll in which the apices of the ridges travel upward is gearedto revolve at a very slow speed. The travel of the rolls in the samedirection at unequal speed, and formed with sharp ridges'or scoresparallel with the axis of the rolls, and having the operative relationdescribed, constitutes an entirety, by which grain, having a' regulatedfeed into the rolls,'is broken in the line of its axis or split open atthe crease by the action of the sharp ridges, so as to expose and freethe dark dust and germ, that it may be separated by bolting the brokenmass. This separation can only be effectively obtained by splitting andbreaking the kernels in comparatively few pieces in the first reduction,and in which there is little loss in the reduction of theflour-producingsubstance. The desired fineness is obtained by passingthe cleaned product of the first reduction through the rolls andsuccessively bolting and reducing the middlings produced by eachseparate operation.

The rolls may be ofany suitable material, and of the size ofcrushing-rolls used for milling purposes.

The form of the ridges or scores is shown in Figs. 3 and 4, in which thefaces a, which form the interdental spaces, are tangential to acircle ofsufficiently less diameter than the roll to give the proper depth to thescores; and the short sides b are radial, or approximately so, and withthe sharp apices form the breaking and cutting parts, which extendparallel with the axis of the cylinder, which causes the kernels toassume horizontal positions within the interdental spaces as theydescend between the upward and downward moving surfaces of the rolls.The roll which presents the short or radial sides of the ridges movingupward has a motion from one-half to about five revolutions perminute,and the roll which presents the short or radial sides of theridges moving downward has a motion of from eighty to three hundredrevolutions per minute, according to the work required. The rolls areset so that the apiees of their ridges cannot lap or touch, but workfree of each other. The differential speed increases the reducing actionand equally distributes the grain between the rolling'surfaces, and theoppositely mov in g operating-surfaces.retard the speed of the materialpassing through the rolls, while the ridges act in a cutting way andwith little pressure, more scraping than squeezing and tearing, andconsequently a larger and cleaner bran is produced, so that itsseparation from the flour-producing substance is more easily effected bythe bolting and cleaning operations. In the first reduction themiddlings are large and the kernels are mostly split along their creaseand cut into pieces, so that the damaging matter in the crease is, to alarge extent, separated from the skin as a preliminary operation, whilein the subsequent operations the bran is scraped, giving themostimportant advantages in the manufacture of flour, in which it is ofthe highest importance to prevent the reduction of the bran.

The rolls are suitably mounted in pairs in a cast-iron frame, one rollbeing carried by adjustable bearin gs and held to the proper operatingrelation by springs and set-screws, as shown, or by other suitablemeans. Two or more pairs of rolls may be arranged for use in one frame,and with a, double feeding apparatus provided with regulating-slides c cand feed-rolls d d, arranged to deliver the material into thedisintegratin g-rollsin quantities suited to the; work and to the speedof the rolls, suitable supply and conducting hoppers being arranged uponthe machine for this purpose. A hopper below receives the product fromthe rolls. In these particulars the arrangement of the rolls, hoppers,and the supporting framework may be as shown,or in any suitable way thatwill give the same compactness and capacity for work.

In the arrangement of the two pairs of rolls the outer ones of each pairrevolve slowly and the inner ones revolve rapidly, and the rolls of eachpair in the same direction, and this arrangement I prefer, and will nowdescribe the manner in which the rolls are so operated.

Upon the shaft 0 of the inner roll, A, of one pair a pulley, f, issecured, from which a band leads to the driving power. A gear-wheel, g,on the shaft of this roll engages with a similar gear, h, on the innerroll, A, of the other pair, so that these rolls are thus revolved inopposite directions at the same fast speed. The

shaft 6, first stated, also carries a pinion, i, which engages with asimilar pinion, 45, upon a shaft,j, crossing the frame at a pointbetween the inner rolls, and carrying a bevel-pinion, k, at the oppositeside of the frame, and

which matches with a bevel-wheel, Z, on a shaft,

1, carried in bearings at the side of the frame. This side shaft, l, isprovided at each end with a worm, m, Fig. 1, one being right and theotherlefthand, and each engaging with a wormwheel, n, on the shaft ofthe outer roll, B, of each pair, so that these rolls are thus revolvedin the same direction as the inner rolls and at slow speed. This gives avery compact and effective arrangement for operating the two pairs ofrolls, as described, from a single driving-pulley, and in which thecross and side shaft connections equally distribute the strain upon themachine. It is obvious, however, that only one pair of rolls may be usedto carry out myinvention. As the sharp ridges of the rolls must not bepressed one into the other, the arrangement for setting theadjusting-roll must be such as to allow it to yield against the pressureof double springs, but prevent it from pressing against the ridges ofthe 'non adjusting roll. In Figs. 5 and 6 I have shown the means bywhich this is effected more clearly, and will now specifically describethem.

The fixed blocks or bearings O C of the inner roll, A, are preferablyset between walls in depressed parts of the top plates of the sideframes, while the slidi ng blocks or bearin gs D D of the adjustableroll B are seated in said depressed parts,and both are secured upontheir seats by a top binder, E, provided with oilcups for theroll-journals. The adjustable roll has a yielding pressure given to itby coiled springs 13, arranged within tubular parts 8, extending inwardfrom the front corners of the side frames on a line with the slidingblocks against which they press; and the means for regulating suchpressure consists of a screwsleeve, 20, provided with a follower, v, atits inner end bearing against the outer end of said springs, and asurrounding screw-sleeve, w, provided with a hand-wheel, F, on its outerend and acollar, y, on its inner end, the screw of the surroundingsleeve fitting the external screw of the inner sleeve. The outerscrewsleeve, w, is secured to the outer end of the tubular frame part 8by the collar '1, so as to be free to be turned by the hand-wheel F,which is at the front of the frame; but being prevented from endwisemovement when so turned to the right, it will screw the inner sleeveinward, and, by its follower v, compress the springs and increase theirpressing force upon the roll. The reverse movement of said hand-wheelswill diminish the pressure of said roll.

I prefer to use double springs, one within the other, and of right andleft pitch, to obtain a uniform pressure. To prevent the contact of theroll-ridges under such pressure, and which would cause them to becomelocked together, stop-studs 0 are arranged between the bearings O and Dand are supported thereby, said studs being provided with screw-nuts p,which are set so as to receive and support the sliding bearin gs, sothat the roll-ridges cannot meet. This is independent of the means bywhich the distance between the rolls is adjusted, and therefore suchadjusting means can never cause the rolls to come in contact. Thesestop-studs have no fixed connection with either bearing-block, and, infact, the sliding blocks can move freely over them. WVhen the roll B isproperly set the nuts o are secured by jamnuts.

The distance which the adjustable roll can yield from the non-adjustableroll is determined by stops formed by the 'inner ends of the tubularparts 8, and against which the sliding blocks will act to prevent theseparation of the rolls beyond a proper limit, so that whether the rollB be adjusted toward or from the roll A such adjustment is limitedbetween the stops 0 on one side of the sliding blocks and by the tubularparts .9 on the other side. It is, however, important in reducingdifferent kinds of grain to set the rolls at diflerent distances apart;and for this purpose I provide screw-stems a, locked by T-heads toextensions r from the sliding bearings and passing centrally through'the springs t, and their pressure-regulating sleeves are fitted ontheir outer ends with hand-nuts G, just outsideof the hand-wheels F,there beingjam-nuts z on the ends of said screw-stems to lock theseouter hand nuts thereon. The hub of the outer hand-nut has a screwfitting the screwstem 00, and it also bears against the outer end of theouter sleeve, 20, and this bearingis necessary to render thefollower-sleeve independent of the outer handnut, so that these handwheels and nuts hear one upon the other in the line oftheir axis andmaintain such relation both in the adjustment of the springs and of theroll by the action of the springs. These screw-stems do not turn intheir connections with the sliding blocks, but the outer handnuts areturned upon them, and if so turned to the right the screw-stems andtheir connected bearing-blocks will be drawn outward against thepressure ofthe springs. The turning of these hand-nuts to the left willallow the bearing-blocks to be forced inward by the springs, and thedistance between the rolls is in this way regulated to suit the work;and when so regulated the jam-nuts. z serve to make the set secure. Thisadjustment of the roll, while being independent of that of the springs,yet the devices for effecting both are combined in a single device andindependent of the means by which the minimum distance between the rollsis effected.

The arrangement for operating the sleevefollowers to and for formingbearings for the outer hand-nuts independent of said sleevefollowers arethe means by which I obtain the combined device for each sliding block.

The tubular parts 8 s of the frame serve to inclose the springs.

It is important to notice that the means for operating the rolls notonly equalize the strain upon both sides of the frame, but the wormgearconnections allow the outer roll to slide toward and from the inner rollwithout effecting such connections; and, besides, the wormgear gives amuch slower motion to the outer roll than could be obtained byspur-gear, which is very important.

I am aware that prior to my invention rolls in pairs for millingpurposes have been run at an unequal speed, in opposite directions, andthat rolls have been made having ribs or surface-corrugations inclinedto the axis, so as to act like shears at the grinding-point, and atwhich point the surface of one roll descends and that of the otherascends with the same speed for grinding bone to flour, and therefore Ido not claim these things broadly. Nor do I claim rolls provided withsharp-ridges or corrugations of ratchet form parallel to theiraxes andrevolving in the same direction with unequal speed.

I claim 1. In a roll-mill for reducing grain to middlings, thecombination of rolls having sharp ridges formed and operatingsubstantially as described, with means for operating the rolls in pairsin the same direction at unequal speed, and for equalizing the strainupon both sides of the frame, the said means consisting of thecross-shaft j, uniting the gear-wheels g h and the pinions i if at oneside of the frame with the inner roll and the bevel-gear 7c 1,connecting, by the side shaft, 1, the worm m thereon with the gear nonthe adjustable roll, at the other side of the frame, as specified.

2. The means herein described for adjusting the distance between therolls, and for regulating the pressure of the adjustable roll,consisting of the screw-stems 00 00, having non-revolving connectionswith the sliding bearings of said adjustable roll, and provided with thehand-nuts G, which turn thereon, the pressure springs t, and theintermatchingscrew-sleeves a w, the inner one, a, provided with abearingfollower for said springs, and the outer one, 10, having thehand-wheel F, and turning upon said inner screw-sleeve, and secured tothe frame by a collar, y, which revolves with it, the said hand-nuts Grhaving a face bearing upon the sleeves of the hand-wheels F, so thatwhile the hand-nuts adjust the rolls, and the sleeves u and to cooperateto adjust the pressure of the springs, the hand-nuts and the handwheelsleeves neither move toward or from the roll-bearings in effecting suchadjustment and pressure, substantially as described.

3. The combination of the roll B, mounted in sliding bearings, thescrew-stems ma, having non-revolving connections with the slidingbearings of said adjustable roll, the hand-nuts G G, turning upon saidscrew-stems, the pressure-springs t, and the intermatching screwsleevesto and w, constructed and having the relation to each bthersubstantially as described, and for the purpose specified, with thejam-nuts 2, on the outer ends of said screwstems for locking the latterwhen the rolls are set the required distance apart, substantially asdescribed.

4. The tubular frame parts 8, in combination with the roll B, mounted insliding bearings, and the cap-binders E therefor, the said slidingbearings provided with the side extensions, r, projecting within saidtubular parts of the frame, which serve as guides for said slidingbearings and as stops to limit their maximum yielding distance,substantially as described.

5. The combination, with means having a fixed connection with the boxesof the roll B for adjusting the distance between the rolls and forlocking such adjustment when made, means for regulating the pressure ofthe adjustable roll, and fixed means fer determining my hand in thepresence of two subscribing witnesses.

OSCAR OEXLE. Witnesses PAUL STETTER, FRANZ MAYER.

